Why does swappiness not work?

We have a RHEL 7 machine, with only 2G of available RAM: free -g total used free shared buff/cache available Mem: 31 28 0 0 1 2 Swap: 15 9 5 so we decided to increase the swappiness to the maximum with vm.swappiness = 100 in /etc/sysctl.conf instead of 10, and used sysctl -p to apply the setting. After some time we checked the status again: free -g total used free shared buff/cache available Mem: 31 28 0 0 2 2 Swap: 15 9 5 as we can see despite the new swappiness setting, we see from free -g that the available RAM stays at 2G. Why? What is wrong here? We expected to see 15G of **used** swap. We also checked: cat /proc/sys/vm/swappiness 100 so everything should work according to the new settings BUT free shows the same situation. What is going here?